1. Technical Field
This invention relates to the field of stored program control telecommunication installations and, in particular, to telephone exchange installations in which an indication of the type of information is sent ahead in advance of each communication to be transmitted.
2. Description of the Prior Art
The invention relates to a circuit arrangement for telecommunication installations, in particular, telephone exchange installations, in which there is sent ahead of each of a plurality of different communications to be transmitted, a corresponding data block indicating the type of information or about the actually existing type of communications. Depending on the possibly continuously varying operating situation of two such telecommunication exchanges or switching systems adapted for the sending and/or receiving of communications and preferably at least partially also for the processing thereof, one is either ready or not ready to receive a message to be emitted from the other depending on the currently existing operating situation and depending on the announced message type. Thus, before a communication transmission, a message concerning the readiness or non-readiness is transmitted in the opposite direction to the type information for signaling the release or suppression of this transmission. Consequently, the communications, information and messages are transmitted in bit portions having a uniform word format.
A circuit arrangement of this kind is already known through German OS No. 33 11 043. Therein, for the preparation of the transmission of a longer communication, first type information is transmitted by which it is announced of what type a communication queued up for transmission is. Since receiving equipments may either be ready or not ready for reception of a communication of a certain communication type depending on the currently existing operating status, by the exchange of type information and a message preceding the communication transmission, it is determined whether or not the intended transmission can take place immediately or must be postponed to a later time.
Systems of this known kind which operate in the stated manner involve the problem of requiring a predetermined time for the exchange of type information and a message in addition to the actual telecommunication. To this problem must be added the requirement for a second predetermined period in the equipment to receive the respective communication and evaluate the respective type information, that is, for the recognition of the respective type of communication as well as for a calling down of the type-specific message corresponding to this type of communication, which must then be made to go out counter to the type information.
It is the object of the invention then in a circuit arrangement of the initially stated kind, to reduce the time requirements for the preparation of a telecommunication transmittal.